Process for the manufacture of iron and steel



'PatentedFeb. 16, 1932 UNITED STATES PATENT OFFICE I JOHAH VA! BOYEN, OFHOBDE, GERMANY, ASSIGNOR TO FIRM VEREINIG'IE STABL .AKTIENGESELLSCHAFT,OF DUSSELDOBF, GERMANY rnocnss FOR THE H ANUFACI'UBE OF IRON AND STEEL17o Drawing. Application iiled February 18, 1828, Serial No. 254,899,and in Germany February 21, 1927.

This invention relates to a process for the manufacture of iron andsteel and has for its ployed in the manufacture of. steam boilers,

oiler tubes and the like but with the steels hitherto in use thistreatment has as a result a reduction in toughness.

It may further be noted that ageing of said cold deformed articlesfurther reduces the toughness and tenacity thereof. This reduction oftoughness may be observed by means of the impact test on a notched bar.

Metallurgists have long been striving to obtain a material which doesnot have the aforementioned undesirable and unfavorable properties. Upto the present time, however, they have not been able to produce anarticle whlch has been subjected to cold deformation, in which thebrittleness produced thereby has been confined to tolerable limits andin which the increase of brittleness caused by ageing These results areobtained by virtue of the fact that the working process consists in adeformation operation, rolling, forging or pressing, which is continuedto the greatest extent possible at a temperature which is below the Arpoint. Thi deformation takes place preferably immediately below said Arpoint since in the range disposable at these temperatures the materialmay be deformed to the greatest extent. The next step consis't-s in anormalizing annealing operatlon carried out at a temperature somewhatabove the Ac point. The last operation is cooling in the am What I claimis:

A process for the manufacture of mild or hard steel insensible againstcold deformation and ageing characterized by the fact that the materialin the course of its working is deformed as extensively as possible attemperatures lying below its ii -transformationpoint, the deformingprocess beginn ng 1 mmediately below the Ar oint and being imished asquickly as possi le, after which operation the material is subjected toa normalizing annealing treatment HERMAN JOHAN VAN ROYEN.

